package middleware

import (
	"github.com/gin-gonic/gin"
)

func Cors() gin.HandlerFunc {
	return func(c *gin.Context) {
		origin := c.Request.Header.Get("origin") //请求头部
		if len(origin) == 0 {
			origin = c.Request.Header.Get("Origin")
		}
		if origin != "" {
			//接收客户端发送的origin （重要！）
			c.Writer.Header().Set("Access-Control-Allow-Origin", origin)
			//允许客户端传递校验信息比如 cookie (重要)
			c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
			c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With")
			//服务器支持的所有跨域请求的方法
			c.Writer.Header().Set("Access-Control-Allow-Methods", "OPTIONS, GET, POST, PUT, DELETE, UPDATE")
			c.Writer.Header().Set("Content-Type", "application/json; charset=utf-8")
			// 设置预验请求有效期为 86400 秒
			c.Writer.Header().Set("Access-Control-Max-Age", "86400")
		}

		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(204)
			return
		}
		c.Next()
	}
}
